Tian Jingjing, Xue Qifan, Tang Xiaofeng, Chen Yuxuan, Li Ning, Hu Zhicheng, Shi Tingting, Wang Xin, Huang Fei, Brabec Christoph J, Yip Hin-Lap, Cao Yong
Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China.
Institute of Materials for Electronics and Energy Technology (i-MEET), Friedrich-Alexander-University Erlangen-Nuremberg, Martensstraße 7, 91058, Erlangen, Germany.
Adv Mater. 2019 Jun;31(23):e1901152. doi: 10.1002/adma.201901152. Epub 2019 Apr 11.
A synergic interface design is demonstrated for photostable inorganic mixed-halide perovskite solar cells (PVSCs) by applying an amino-functionalized polymer (PN4N) as cathode interlayer and a dopant-free hole-transporting polymer poly[5,5'-bis(2-butyloctyl)-(2,2'-bithiophene)-4,4'-dicarboxylate-alt-5,5'-2,2'-bithiophene] (PDCBT) as anode interlayer. First, the interfacial dipole formed at the cathode interface reduces the workfunction of SnO , while PDCBT with deeper-lying highest occupied molecular orbital (HOMO) level provides a better energy-level matching at the anode, leading to a significant enhancement in open-circuit voltage (V ) of the PVSCs. Second, the PN4N layer can also tune the surface wetting property to promote the growth of high-quality all-inorganic perovskite films with larger grain size and higher crystallinity. Most importantly, both theoretical and experimental results reveal that PN4N and PDCBT can interact strongly with the perovskite crystal, which effectively passivates the electronic surface trap states and suppresses the photoinduced halide segregation of CsPbI Br films. Therefore, the optimized CsPbI Br PVSCs exhibit reduced interfacial recombination with efficiency over 16%, which is one of the highest efficiencies reported for all-inorganic PVSCs. A high photostability with a less than 10% efficiency drop is demonstrated for the CsPbI Br PVSCs with dual interfacial modifications under continuous 1 sun equivalent illumination for 400 h.
通过应用氨基官能化聚合物（PN4N）作为阴极界面层和无掺杂空穴传输聚合物聚[5,5'-双（2-丁基辛基）-（2,2'-联噻吩）-4,4'-二羧酸酯-alt-5,5'-2,2'-联噻吩]（PDCBT）作为阳极界面层，展示了一种用于光稳定无机混合卤化物钙钛矿太阳能电池（PVSC）的协同界面设计。首先，在阴极界面形成的界面偶极降低了SnO的功函数，而具有更深最高占据分子轨道（HOMO）能级的PDCBT在阳极提供了更好的能级匹配，导致PVSC的开路电压（V）显著提高。其次，PN4N层还可以调节表面润湿性，以促进具有更大晶粒尺寸和更高结晶度的高质量全无机钙钛矿薄膜的生长。最重要的是，理论和实验结果都表明，PN4N和PDCBT可以与钙钛矿晶体强烈相互作用，这有效地钝化了电子表面陷阱态，并抑制了CsPbI Br薄膜的光致卤化物偏析。因此，优化后的CsPbI Br PVSC表现出界面复合减少，效率超过16%，这是全无机PVSC报道的最高效率之一。在连续1个太阳等效光照400小时的条件下，具有双界面修饰的CsPbI Br PVSC表现出高光稳定性，效率下降不到10%。
